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    The effects of cryogenic-treated carbide tools on tool wear and surface roughness of turning of Hastelloy C22 based on Taguchi method
    (Springer London Ltd, 2016) Akincioglu, Sitki; Gokkaya, Hasan; Uygur, Ilyas
    In this study, Taguchi method has been applied to evaluate the effect of cryogenically treated tools in turning of Hastelloy C22 super alloy on surface roughness. The optimum parameters (cryogenic treatment, cutting speed, and feed rate) of turning were determined by using the Taguchi experimental design method. In Taguchi method, L9 orthogonal array has been used to determine the signal noise (S/N) ratio. Analysis of ANOVA was carried out to identify the significant factors affecting surface roughness. The statistical analysis indicated that feed rate, with a contribution percentage as high as 87.64 %, had the most dominant effect on machining performance, followed by the cryo-treated tools treatment and cutting speed, respectively. The confirmation tests indicated that it is possible to improve surface roughness significantly by using the Taguchi method. Surface roughness was improved by 28.3 and 72.3 % by shallow (CT1) cryogenic treatment and deep cryogenic treatment (CT2) applied on cementite carbide tools (UT). It found that wear resistance of tungsten carbide insert was increased by shallow and deep cryogenic treatments.
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    Effects of cryogenically treated physical vapor deposition-coated tools on the turning performance of nickel-based superalloy
    (Sage Publications Ltd, 2023) Gokkaya, Hasan; Akincioglu, Sitki
    In recent years, cryogenic treatment has been applied to improve the performance of cutting tools. Improving the performance of cutting tools can improve the surface qualities of workpiece and reduce costs. Nickel-based superalloys are difficult to machine. It is necessary to improve the machinability properties of these hard-to-machine alloys and to increase the product quality. In this study, the effects of cryogenically treated physical vapor deposition-coated tools on the turning performance of nickel-based Hastelloy C22 superalloy were investigated. Deep cryogenic treatment (-145 degrees C) and shallow cryogenic treatment (-80 degrees C) were applied to the physical vapor deposition-coated tools. Experiments were carried out under dry conditions. The cutting parameters selected for the machining were cryogenically treated cutting tools, cutting speed, and feed rate. The deep cryogenic treatment had a favorable influence on the performance of the physical vapor deposition-coated carbide inserts. Thanks to the deep cryogenic treatment applied to the cutting tools, 99.5% and 19.7% improvement in surface roughness and cutting forces were achieved, respectively, compared to the untreated tool. The deep cryogenic treatment contributed more to the wear resistance of the tools than the shallow cryogenic treatment. A slight increase in the hardness and electrical conductivity of the tools was detected thanks to the cryogenic treatment.
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    Investigation of the effect of AWJ drilling parameters for delamination factor and surface roughness on GFRP composite material
    (Emerald Group Publishing Ltd, 2022) Altin Karatas, Meltem; Gokkaya, Hasan; Akincioglu, Sitki; Biberci, Mehmet Ali
    Purpose The purpose of this study is to optimize processing parameters to get the smallest average surface roughness (Ra) and delamination damage (F-d) values during drilling via abrasive water jet (AWJ) of the glass fiber-reinforced polymer composite material produced at [0 degrees/90 degrees](s) fiber orientation angles. Design/methodology/approach Drilling experiments were done via AWJ with three-axis computer numerical control (CNC) control system. Machine processing parameters such as water pressure of 3,600, 4,300, 4,800 and 5,300 bar; stand-off distance of 1, 2, 3 and 4 mm; traverse rate of 750, 1,500, 2,000 and 3,000 mm/min; and hole diameters of 8, 10, 12 and 14 mm have been selected. The effects of processing parameters in drilling experiments were investigated in conformity with the Taguchi L-16 orthogonal array and the data obtained were analyzed using Minitab 17 software. The signal/noise (S/N) ratio was taken as a basis for evaluating the test results. Optimum processing conditions were determined by calculating the S/N ratio for both Ra and F-d in conformity with the smaller is better approximation. The effects of processing parameters on Ra and F-d were statistically investigated using analysis of variance, S/N ratio and Taguchi-based gray relational analysis. Ra and F-d were predicted by evaluating with the ANN model and were predicted with the least amount of error. Findings It has been determined that the most effective parameter for Ra and F-d is the water pressure and then the stand-off distance. Originality/value The novel approach is to reduce cost and the time spent by using Taguchi optimization as a result of AWJ drilling the material in this fiber orientation [0 degrees/90 degrees](s).
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    A review of cryogenic treatment on cutting tools
    (Springer London Ltd, 2015) Akincioglu, Sitki; Gokkaya, Hasan; Uygur, Ilyas
    Enhancing the performance of cutting tools is an important factor in reducing production costs. Cutting tools are subjected to processes such as heat treatment and coating in order to improve their performance. Cryogenic treatment, which is also known as sub-zero heat treatment, has made significant contributions to the improvement of wear resistance, tool life, dimensional integrity, and product quality of cutting tools. The mode of application of cryogenic treatment and the type of cutting tool both affect tool performance. Therefore, it is necessary to examine the way cryogenic treatment is applied to cutting tools and its effects on their performance. This study reviews the literature on the performance of cryo-treated cutting tools.
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    Taguchi optimization of surface roughness in the turning of Hastelloy C22 super alloy using cryogenically treated ceramic inserts
    (Sage Publications Ltd, 2020) Akincioglu, Sitki; Gokkaya, Hasan; Akincioglu, Gulsah; Karatas, Meltem A.
    Cryogenic treatment has been used in recent years to improve the performance of cutting tools. This study evaluated the machinability of a nickel-molybdenum-based super alloy using cryogenically treated (-80 celcius and -145 celcius) ceramic inserts under dry turning conditions. Three cutting speeds (350, 400, and 450 m/min), three feed rates (0.1, 0.2, and 0.3 mm/rev), and a 1-mm fixed cutting depth were used in the turning tests. Experiments were conducted using the Taguchi orthogonal array L(27)design. The factors affecting the surface roughness (Ra) were determined via analysis of variance. The effect of cryogenic treatment type (shallow and deep), cutting speed, and feed rate on surface roughness was investigated. Results of the analysis determined that the feed rate was the major parameter that affected surface roughness and that the deep cryogenic treatment was more effective. The regression analysis confirmed that the experimental results and the predicted values were within the 95% confidence interval. The most effective parameter affecting the surface roughness was feed rate at a contribution of 57.9%. The contribution of the cutting tool type to the surface roughness was 28.5%. The results obtained showed that the surface roughness can be optimized for turning the Hastelloy c22 super alloy with the Taguchi method.